The purpose of the article is to trace the transformation of ideas about eidolon and simulacrum in the Platonic tradition and in Gilles Deleuze, to understand their cardinal difference and possible similarities. Deleuze, at the beginning of his essay “Plato and the Simulacrum”, says, repeating Nietzsche, that the task of modern philosophy is to overthrow Platonism, meaning “the abolition of the world of essences and of the world of phenomena”. Deleuze rejects the equality of the Same and the Other, as it was accepted in Plato, in favor of the latter: thus, he rejects the very idea of paradigm as the principle of the “One” and, accordingly, disregards copies as similarities, coming to the concept of "the
Other within the Other" as an infinite sliding on the “surface” of simulacra, that is, some “ghostly likenesses” without any relation to the idea of resemblance. There arises a picture of a phantasmal world of continuous immanence that presupposes no transcendence, no hierarchy and depth, a picture of “chaosmos” and “chaodyssey”, very close to what Plato describes in the 7th hypothesis of the dialogue Parmenides. The article examinesthe problem of Socrates’ resemblance to a sophist, which is posed by both Plato and Deleuze; the role of transcendence in distinguishing those two in Plato is shown. The role of the chora and the Other in Plato is demonstrated in the context of the concept of similarities and phantasms, and Plotinus’ development of this theme in the theme of the intelligible matter. In conclusion, a comparison is made between Plotinus’ “unenlightened” primary otherness and Deleuze’s “chaosmos”.